Anne Washburn’s new play sounds like the premise for the movies The Big Chill and The Return of the Secaucus Seven – a group of old friends reunite in a bucolic ranch house in the Texas Hill Country after one of them dies – but if it were a movie the producers would surely have insisted that it not be called “Antlia Pneumatica.” The title is named after a constellation, and it’s the first clue that Washburn’s play will take an other-worldly turn, something anybody acquainted with such previous work of hers as “Mr. Burns, a post-electric play” might have suspected in any case.

The friends in their early 40’s have gathered from different parts of the country to spread the ashes of a friend with whom they each had lost touch years before. They spend most of their time standing around a kitchen island making pies and salads. But from the start things seem amiss. Objects go missing that nobody can account for. An ex-boyfriend shows up without having been invited, saying he was told about the gathering from another friend – but somebody in the group seems to remember that that other friend died 14 years ago. Characters recall events that they then dismiss as dreams — but wonder whether they are real. A late-arriving twist puts “Antlia Pneumatica” in the realm of a ghost story.

But the disorientation in “Antlia Pneumatica” is not limited to the characters. Most scenes in the play occur on a stage that is lit too darkly to see clearly. At one point, Nina (Annie Parisse) and her long-ago boyfriend Andre (Rob Campbell) speak in pitch dark, all that’s visible the faint stars above (including, you guessed it, the Antlia Pneumatica.) Other scenes occur entirely off-stage, recorded voices of characters we never see. Much is left unresolved and unexplained.

In theory, this double disorientation of both characters and audience should be thought-provoking, the mystical and mysterious atmosphere intriguing. In practice, it comes off as vague. This is in part because, ironically or not, the more accessible scenes are so appealing — the ones in which the characters reminisce about their times together, and riff on parenthood and getting older, and, yes, on death. As they get reacquainted, we get to know them. Annie Parisse creates an attractive Nina, the daughter of a long-deceased celebrity singer-songwriter whose long-neglected ranch she has inherited, and who is the host of this gathering. April Mathis plays her younger sister Liz, and their interaction has the feel of concretely observed sibling dynamics. The character Len gets the best lines, both the funniest and most arresting, and Nat DeWolf makes the most of them. Crystal Finn as Bama sweeps us up with her enthusiasm even as she delivers the spookiest reveal.

Anne Washburn’s sometimes unnerving imagination and her eagerness to experiment with form and theatrical effect help make her a playwright whose work stands out even when you can’t quite stand or understand it. Her wit and ear for dialogue make attendance worthwhile even when she’s leaving you in the dark.